1. Field of the Invention
The present invention relates to input devices for computers and word processors and, more particularly, to ergonomic input devices for minimizing repetitive use injuries and for accommodating users of different physical abilities.
2. Description of Related Art
The development of ergonomically designed keystroke input devices as well as ergonomically designed cursor tracking devices has resulted from an increased awareness and identification of physical problems associated with the use of conventional typewriter-like keyboards and mice. An ergonomically designed keyboard attempts to create a key layout that reduces finger travel and fatigue; promotes a more natural hand, wrist, and arm typing posture through design and support structures; or employs various key activation schema in order to enhance typing performance. An ergonomically designed mouse promotes more natural hand, wrist, and finger positions.
Owing to the proliferation and availability of data entry systems, there has been a dynamic growth in the use of keyboard devices. Various annoying and debilitating muscular syndromes have accompanied this expansion, resulting from the repetitive and fatiguing hand, wrist, and finger motions that are required in the use of conventional typewriter-like keyboards. There has been a growing concern over neuromuscular injuries among clerical workers, journalists, computer programmers, and others who use computers or typewriters extensively. These injuries, one widely publicized of which is carpal tunnel syndrome, translate not only into pain and potential disability for the affected users, but also into significant loss of money, time, and productivity for businesses. Attention to these problems is not new in the art, as is evidenced by many serious attempts to alleviate keyboard-use "injuries" through innovative keyboard layouts, architectural designs, and support devices for the user's body parts to encourage "correct" posture during the use of keyboards.
Typewriter key force, repetition, posture, rest, and stress are major factors to be considered in controlling and eliminating keyboard-related injuries (KRIs). Analysis of each factor, both independently and in relation to one another, is necessary in designing a keyboard that eliminates or reduces KRIs, force and repetition being perhaps the most important in the development of an ergonomically designed keyboard. Force is related to the musculature and conformation of the fingers and hands, which place limitations on their ability to perform a given task.
An abundance of human-computer interaction literature has suggested that some of the recently developed alphanumeric input devices may be more efficient, easier to learn, and may cause less physical trauma than conventional typewriter-like keyboards. Of these recently designed keyboards, most incorporate one or more design features that enhance typing performance and reduce or eliminate fatigue or injury. These design features include: (1) splitting the keyboard to minimize wrist deviations; (2) key contouring and flexible key mapping to minimize finger travel; (3) built-in hand and arm support; (4) a ternary capability in which keys rock back and forth to type; (5) a capability to rotate and tilt the device into numerous positions; and (6) a chordal capability, in which more than one key must be depressed for a single character to be output.
In reference to eliminating or reducing force and repetition fatigue factors, three approaches taken in the prior art are illustrated in U.S. Pat. No. 4,332,493, issued to Einbinder, U.S. Pat. No. 4,849,732, issued to Dolenc, and U.S. Pat. No. 5,178,477, issued to Gambaro.
Other issued patents that address modified keyboard and character arrangements include U.S. Pat. No. 4,244,659, issued to Malt, U.S. Pat. No. 4,509,873, issued to Ryan, U.S. Pat. No. 4,579,470, issued to Casey, U.S. Pat. No. 4,597,681, issued to Hodges, U.S. Pat. No. 4,655,621, issued to Holden, U.S. Pat. No. 5,006,001, issued to Vulcano, U.S. Pat. No. 5,017,030, issued to Crews, U.S. Pat. No. 5,029,260, issued to Rollason, U.S. Pat. No. 5,067,834, issued to Szmanda, U.S. Pat. No. 5,087,910, issued to Guyot-Sionnest, and U.S. Pat. No. 5,137,384, issued to Spencer. None of these addresses the issues of keyboard use and motion injuries.
Computing devices are regularly used for relatively long periods of time by people of all ages and abilities, it is becoming increasingly important that a device also accommodate the physically challenged. Prior art devices in general demand considerable manual and digital dexterity to operate, making them difficult for some portion of the population to utilize efficiently and effectively.
Two types of hand rests, both for partial and full hand support, have been identified in the prior art. One kind acts as an actuator and is not intended to support a substantial part of the weight of the hand, but instead to impart some function. Another type of hand rest known in the art serves only to space the fingers from the proximity-actuated keys to avoid accidentally operating the keys.
A further problem in the art is the use of input devices in hostile environments or under nonideal conditions, such as while wearing gloves. Standard keyboards are extremely difficult to use without unencumbered fingers, owing to the conventional spacing and key layouts of such devices.
My previous patent, "Ergonomic Human-Computer Interface Apparatus and Method," Ser. No. 08/473,325, filed Aug. 11, 1993, now issued U.S. Pat. No. 5,473,325, has addressed the ergonomic effects of keyboards with a dome-shaped input device, used either alone or in pairs via chording, that is rocked from a home position to actuate a keystroke.